The family of bioactive lipids known as the leukotrienes exert pharmacological effects on respiratory, cardiovascular and gastrointestinal systems. The leukotrienes are generally divided into two sub-classes, the peptidoleukotrienes leukotrienes C.sub.4, D.sub.4 and E.sub.4) and the dihydroxyleukotrienes (leukotriene B.sub.4). This invention is primarily concerned with the hydroxyleukotrienes (LTB) but is not limited to this specific group of leukotrienes.
The peptidoleukotrienes are implicated in the biological response associated with the "Slow Reacting Substance of Anaphylaxis" (SRS-A). This response is expressed in vivo as prolonged bronchoconstriction, in cardiovascular effects such as coronary artery vasoconstriction and nnmerous other biological responses. The pharmacology of the peptidoleukotrienes include smooth muscle contractions, myocardial depression, increased vascular permeability and increased mucous production.
By comparison, LTB.sub.4 exerts its biological effects through stimulation of leukocyte and lymphocyte functions. It stimulates chemotaxis, chemokinesis and aggregation of polymorphonuclear leukocytes (PMNs).
Leukotrienes are critically involved in mediating many types of cardiovascular, pulmonary, dermatological, renal, allergic, and inflammatory diseases including asthma, adult respiratory distress syndrome, cystic fibrosis, psoriasis, and inflammatory bowel disease.
Leukotriene B.sub.4 (LTB.sub.4) was first described by Borgeat and Samuelsson in 1979, and later shown by Corey and co-workers to be 5(S),12(R)-dihydroxy-(Z,E,E,Z)-6,8,10,14-eicosatetraenoic acid. ##STR2## It is a product of the arachidonic add cascade that results from the enzymatic hydrolysis of LTA.sub.4. It has been found to be produced by mast cells, polymorphononuclear leukocytes, monocytes and macrophages. LTB.sub.4 has been shown to be a potent stimulus in vivo for PMN leukocytes, causing increased chemotactic and chemokinetic migration, adherence, aggregation, degranulation, superoxide production and cytotoxicity. The effects of LTB.sub.4 are mediated through distinct receptor sites on the leukocyte cell surface that exhibit a high degree of stereospecificity. Pharmacological studies on human blood PMN leukocytes indicate the presence of two classes of LTB.sub.4 -specific receptors that are separate from receptors specific for the peptide chemotactic factors. Each of the sets of receptors appear to be coupled to a separate set of PMN leukocyte functions. Calcium mobilization is involved in both mechanisms.
LTB.sub.4 has been established as an inflammatory mediator in vivo. It has also been associated with airway hyper-responsiveness in the dog as well as being found in increased levels in lung lavages from humans with severe pulmonary dysfunction.
By antagonizing the effects of LTB.sub.4, or other pharmacologically active mediators at the end organ, for example airway smooth muscle, the compounds and pharmaceutical compositions of this invention are valuable in the treatment of diseases in subjects, including human or animals, in which leukotrienes are a factor.